A purpose of the invention is to improve containers made of plastic material, the non-cylindrical body of which is reinforced by reinforcing means composed of peripheral grooves. It can be applied to any type of container the body of which has at least one wall part with an appreciably flat relief, which is the case with bottles. It also applies, and quite particularly, to bottles the body of which has a cross section that is generally quadrilateral in shape, with rounded corners, intended to contain so-called flat liquids, i.e., with no internal pressure.
Throughout the text of the present application, the terms relating to a spatial position of a container or of various parts of a container relative to each other should be understood as being when the container is standing, that is, oriented vertically along its longitudinal axis, with the bottom down and the neck up. This is true particularly, but not exclusively, for the terms above, below, lower, upper, up, down, height, vertical, horizontal, etc.
It is known that containers made of plastic material are becoming lighter and lighter, which creates problems in obtaining good mechanical strength both in the longitudinal as well as in the transversal direction.
Consequently, when they are picked up, especially after being opened, they have a tendency to crush, which could cause the contents to be discharged, particularly when said contents are liquid.
When the containers are closed, compression forces occur when they are stacked on top of each other during storage or transport. If their walls are not sufficiently rigid, the result is an increase in the cross section of the body of each of the containers supporting others. This is due to the fact that the pressure exerted above a container causes its shoulders to sag, thus increasing the internal pressure of the container, which then affects the internal walls. If the containers are strapped to each other, the risk is then that, when
the cross section is increased, the stresses exerted between two adjacent containers become excessive, which can lead to mutual damage by compression, for example.
These disadvantages are partially remedied by producing containers having a succession of reinforcing grooves at the periphery of their body. However, although this solution has proven generally satisfactory for containers having a body with cylindrical cross section, both when they are handled after being opened as well as when they are stacked, this is not the case for containers having at least one wall part with appreciably flat relief, such as containers having a body with cross section that is generally quadrilateral in shape, with rounded corners, particularly when they are stacked. This frequently results in a significant increase in their cross section, by outward deformation of the parts of flat walls between two successive grooves.
These phenomena become more acute as the internal volume of the containers increases (more liters) and/or when the hydrostatic pressure exerted by their contents is large. Indeed, when forces due to hydrostatic or other pressure tending to increase the cross section of the walls of a container are present, they tend to be exerted more at the center of the flat or appreciably flat areas than on their edges. This explains the outward deformations of the parts of walls between two successive grooves that can be observed in these known containers.
A purpose of the invention is to remedy these disadvantages.
According to the invention, a container made of plastic material, having a body oriented along a longitudinal axis, with a non-cylindrical wall around this axis, the wall being reinforced by peripheral grooves oriented along planes that are appreciably perpendicular to said longitudinal axis, at least one part of said wall having an appreciably flat relief and being traversed by several grooves, is characterized in that the width of each groove traversing the part of wall having an appreciably flat relief is variable, the variation in width of each of said grooves being such that it is less wide at its end in said wall part than in the middle of its crossover.
It will be noted that this special structure makes it possible to avoid significant outward deformations of the wall parts that are appreciably flat, between two successive grooves.
According to another feature, a projection of the bottom of a groove, on its orientation plane that is appreciably perpendicular to said longitudinal axis, traversing a part of wall having an appreciably flat relief, has, at least along the crossover, a curved profile with a concavity turned toward the outside of the wall.
This particular shape gives greater rigidity to the bottoms of the grooves, which makes it possible to limit the deformations they undergo during recovery from stresses.
According to another feature, the walls of the grooves have a curved profile.
In this way the creation is avoided of angular areas that could break under the effect of stresses due to pressure, shock or other phenomena.